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May 31, 2012 -- There are fewer cavities in the United States today than there were two decades ago, the CDC reports, but not every population group has shown the same amount of improvement.

According to new estimates released today, at least 1 in 5 Americans has one or more untreated cavities, and the poorer you are, the more likely you are to be one of the untreated 20%, at least among adults.

Non-Hispanic blacks and Mexican-Americans accounted for a large number of those not receiving care for their cavities, also known as dental caries. More than 60% of African-Americans had lost at least one tooth, compared to just under 50% of whites and Mexican-Americans.

"Dental caries both untreated and treated and tooth loss are key indicators of oral health and are used to monitor oral health status in the United States and internationally," the authors write.

The National Center for Health Statistics, a division of the CDC, prepared the report using data from the National Health and Nutrition Examination Survey for the years 2005 to 2008. The annual survey involves a random sampling of about 5,000 Americans. Here are the report's key findings:

Oral Health by Age

20% of children aged 5 to 11 and 13% of teens between the ages of 12 and 19 had at least one untreated cavity.

25% of adults between the ages of 20 and 44 had at least one untreated cavity.

20% of adults over 65 had at least one untreated cavity.

39% of children and 52% of teens had a dental restoration, such as a filling or root canal.

Restoration rates were nearly 90% for adults over 65.

Oral Health by Ethnicity and Poverty Level

34% of non-Hispanic blacks and 31% of Mexican-Americans had untreated cavities compared to 18% of whites.

Adults between 20 and 64 were more than twice as likely to have untreated cavities if they were living in poverty (42% vs. 17%).

25% of children and teens living in poverty had untreated cavities.

Among adults, nearly 90% of whites had had dental restoration, compared to 68% of Mexican-Americans and 73% of non-Hispanic blacks.

Children and teens living in poorer households were much less likely to have sealants than children and teens in higher-income families (20%-22% vs. 32%).

60% of adults in households living in poverty had lost at least one permanent tooth. 32% of non-Hispanic blacks over 65 had lost all their teeth, compared to 22% of whites and 16% of Mexican-Americans.